Fuel cells efficiently and electrochemically convert fuel into electric current, which may then be used to power electric circuits, such as drive systems for vehicles. A fuel cell containing a proton exchange membrane is an electrochemical device that converts chemical energy to electrical energy using hydrogen as fuel and oxygen/air as oxidant. A typical proton exchange membrane fuel cell is generally composed of five layers that form a fuel cell membrane electrode assembly. The membrane electrode assembly includes a solid polymer electrolyte proton conducting membrane, two gas diffusion layers, and two catalyst layers.
Catalyst performance is directly tied to fuel cell performance. Catalyst typically has a carbon support on which a precious metal group is supported. During potential cycling, the carbon surface of the carbon support electrochemically oxidizes to form surface-bound oxides (carbonaceous species with oxygen containing functional groups like carboxyl, carbonyl, etc.) and gaseous carbon dioxide. Carbon dioxide is a product of complete oxidation processes, while surface oxides are formed from incomplete oxidation pathways. Some surface oxides, however, can be further oxidized to carbon dioxide. The oxidation of carbon results in carbon corrosion and thus carbon mass loss and decreased catalyst activity. Measuring catalyst performance and durability is a key parameter in improving the efficiency and cost of fuel cells.